Promoter CpG methylation status in porcine Lyn is associated with its expression levels

Resistance to disease and improvement of product quality are important goals in pig farming. Tyrosine Protein Kinase Lyn (LYN) is one of several Src-family tyrosine kinases in immune cells. This protein functions both as a positive and negative regulator of B cell activation, and regulates signaling pathways through phosphorylation of inhibitory receptors, enzymes and adaptors, which suggested that LYN could be correlated with immunity and can be considered as a candidate gene to study in disease resistance. Until now, the profiles of expression and transcriptional regulation of the LYN gene in pig breeds different in immune capacity remain unclear. Using real-time PCR, it indicated that porcine LYN mRNA expressed mainly in immune organs including the spleen, duodenum and liver. Furthermore, Dahuabai pigs (a kind of Chinese indigenous pig breeds with higher immune capacity) showed significant higher LYN mRNA expression levels than that in Landrace. Methylation analysis indicates that LYN expression levels were associated with the methylation status of the LYN promoter, and methylation of the novel CpG site at -1268C/-1267G generated by transposition at -1267 (A→G) results in up-regulating transcriptional activity of this gene. Interestingly, the base A located in -1267 mainly exhibited in landrace while the base G mainly in Dahuabai pigs. These results might contribute to study the function of this gene in pig breeding for disease resistance.